All quest issues have been traced back to one phasing bug, which is being worked on. Nothing gamebreaking. I didn't have a single crash or lag issue this beta, and I didn't see zone chat exploding with complaints about it as it had before. I also don't think that a few people complaining about launcher issues constitutes "tons", much less a game-breaker.
Most of the problems that get worse at launch have to do with login issues, and guess what's been better and better over the last 3 stress tests?